1. Field of the Disclosure
The present disclosure relates to a touch screen panel, and more particularly, to a capacitive type touch screen panel.
2. Discussion of the Related Art
With a development of various portable electronic devices such as a mobile phone and a notebook computer, a demand for flat display devices to be applied to the various portable electronic devices has been increased steeply.
For example, the flat display devices may include a liquid crystal display apparatus, a plasma display panel, a field emission display device, and a light emitting diode display device. Among the above flat display devices, an application of the liquid crystal display apparatus is gradually increased owing to advantageous of mass production technology, easy driving, high quality image with good resolution, and large-sized screen.
A touch screen is widely used as a substitute for an input device such as a mouse or a keyboard according to the related art, wherein the touch screen facilitates to directly input information to a screen through the use of finger or pen.
The touch screen panel is largely classified into a resistive type and a capacitive type. In this case, the resistive type senses a change of resistance value according to a contact between two substrates if a pressure is applied to a screen by the use of finger or stylus pen. Meanwhile, the capacitive type senses a change of capacitance according to a user's touch.
The capacitive type is advantageous in that it can decrease a thickness of the touch screen panel in comparison with that of the resistive type, it can improve endurance of a touch pad, and it can reduce malfunction caused by an external pressure. Furthermore, the capacitive type enables to perform a multi-touch function by freely expanding or reducing an image with two fingers. Accordingly, there is a recent trend toward high preference of the capacitive type.
FIG. 1 illustrates a flat display device with a capacitive type touch screen panel according to the related art.
Referring to FIG. 1, the capacitive type touch screen panel according to the related art includes a first electrode 120 formed in a first direction, a second electrode 130 formed in a second direction being perpendicular to the first direction, a connection line 140, and a touch pad 150.
The touch screen panel senses a change of capacitive between the first electrode 120 and the second electrode 130 according to whether or not there is a user's touch, to thereby sense a user's touch position.
The first electrode 120 is driven as a driving electrode to which a touch driving signal for sensing a user's touch is applied, and the first electrode 120 is connected with the touch pad 150 through the connection line 140. In this case, the touch pad 150 is connected with a driving electrode driver (not shown) for supplying the touch driving signal for sensing a user's touch through an FPC.
The second electrode 130 is driven as a sensing electrode for sensing a change of capacitance according to a user's touch, and the second electrode 130 is connected with the touch pad 150 through the connection line 140. In this case, the touch pad 150 is connected with a sensing electrode driver (not shown) for sensing a change of capacitance according to a user's touch by the use of FPC.
The sensing electrode driver (not shown) senses a user's touch position by comparing the sensed touch capacitance with a reference capacitance, and outputs the sensed touch position.
The touch screen panel is provided on a liquid crystal panel 110. As shown in FIG. 1, a predetermined portion of the second electrode 130 of the touch screen panel, which is not overlapped with the first electrode 120, is exposed to the liquid crystal panel 110, whereby the exposed portion of the second electrode 130 is influenced by noise generated in the liquid crystal panel 110.
Thus, the touch screen panel has problems of low touch sensitivity and accuracy. For example, since the capacitive type touch screen panel senses the change of capacitance according to a user's touch, it is very sensitive to the noise. That is, even though the capacitive type touch screen panel is not touched by a user, there might be malfunction or error of sensing a user's touch.